According to the Pokemon Global Link Website, the Pokemon Global Link Service will be closing down for Pokemon Black/White and Pokemon Black 2/White 2 on January 14th, 2014. All Dream World activity will be shut down after this point.

The new Pokemon Global Link, which will link to Pokemon X and Pokemon Y, will be up and running in October.

You will no longer be able to change C-gear skins, Musical and Pokedex Skin Customization Options after January 14th, 2014.

The GTS will still be available for Pokemon trades and Random Matchups in Free Mode will still be available, but Random Matches in Rating Mode and your trade/battle history will no longer be accessible.

New users and players with additional games will be unable to register for the Dream World after 10/12/13.

Not sure how many of you use the Global Link, but I for one am not particularly happy to hear about this... I suppose it was inevitable, but I'm going to miss the Dream World. T_T

Note: Read about this a day or two ago. It raises an interesting issue. If Nintendo is shutting down online multiplayer, this is a HUUUUUUGE deal considering how new the games are, but if this is just an ARG thing, it's still a big deal, but less so.